Method of applying an antifreeze product

ABSTRACT

A method of protecting structures and articles from environmental exposure uses a semi-permanent or temporary in situ formed film or tarp to cover the protected articles. The film is environmentally safe and biodegradable. The film also may function as a release film to protect surfaces, such as aircraft wings and refrigeration surfaces, from ice accumulation and may act as a confining barrier to control particulate materials during transportation.

This application is a divisional application of U.S. patent applicationSer. No. 08/312,569 filed Sep. 26, 1994, which is a divisionalapplication of U.S. patent application Ser. No. 07/950,934 filed Sep.24, 1992, now abandoned.

FIELD OF THE INVENTION

The invention relates to methods of protecting articles fromenvironmental exposure, such as materials stored or transported in theopen air and/or exposed to rain, ice, sun and other environmentalfactors. The invention also relates to methods of confining particulateand other materials using a semi-permanent or temporary protective film.

BACKGROUND OF THE INVENTION

The complications associated with the transportation and storage ofmaterials which can freeze and clump together during the colder periodsof the year has become a major commercial problem. Such materials aretransported and stored primarily in open vehicles and containers,accessible to potential ice generating precipitation including rain,sleet and snow. The problem is particularly acute in transportation ofcoal, iron ore and other minerals in open rail cars and trucks. As theloaded cars and trucks are moved across the country, the material in thezone immediately adjacent the outer walls of the vehicles gets coldfaster than the main body of material. Moisture subsequently condensesin this zone and the material begins to aggregate as the moisturefreezes, acting as a cement. This condensation, coupled with themoisture from rain, sleet and snow which tends to collect adjacent tothe container walls causes a defined layer of material-incorporated iceto harden adjacent to and become attached to the walls. As much as 20percent of the material may remain frozen in the car. The purchaser ofthe material has ordered 100 percent and received 80 percent!Furthermore, the shipper has to pay to haul that 20 percent of thematerial back to the mining site. If the material freezes in unevenweight distributions, which it often does, the shipper cannot move thecar until they have removed the rest of the material in order to keepthe cars balanced and avoid potential derailments. This wall-adheringfrozen portion therefor makes material unloading difficult through thenormal automated procedures and requires people with chipping tools toenter the partially unloaded containers to manually remove the remainingiced layer stuck on the walls.

A problem also arises when moisture leaches corrosive compounds from thecontained particulate materials, even at temperatures at and belowfreezing. Storage containers and vehicles such as railcars and truckbeds are made of iron containing metals which, tend to rust and corrodeexcessively because of this corrosive moisture in contact with thewalls. This corrosive action thereby shortens the expected lifetime ofsuch containers and vehicles.

Other problems arise in transporting particulate material, includingcoal, gravel, refuse and the like in open vehicles. Often dust andparticulates are blown and bounced out of the containing vehicle andcreate a hazard to following traffic and an eyesore on the roadway. Inaddition, transported and stored materials, such as structural steel,machines and machine components may corrode and degrade when subjectedto the elements by being stored or transported in the open air. Rain,sunlight, salt spray, pollution and other environmental factors canattack unprotected structures. Containers, tarps and other protectivecoverings of a permanent nature have been used, to protect structures,but these methods are expensive, use bulky objects requiring storage andwhich also must be disposed of when no longer in use. Disposal of oldtarps, containers and structures also creates an environmental problem.These articles are unsightly, occupy landfill space, or require otherexpensive or environmentally intrusive disposal.

The compositions of this invention are also useful in de-icing andprotecting external aircraft components from freezing during the periodof time surrounding take-off. Other structures may also be protectedfrom ice accumulation. During severe cold weather conditions, the wingsand body portions of aircraft will become coated with ice, sleet andsnow and such build-up must be removed from the aircraft prior totake-off. In fact, plane crashes have occurred because the build-up wassufficient to prevent the aircraft from gaining proper altitude aftertake-off. Various systems are presently used to prevent such build-upsand to remove layers of ice, sleet and snow immediately prior totake-off. However, no completely satisfactory system has been developed.

The prior art details several attempts at correcting these problems.Some inventors have attempted to correct the problems only after theparticulate material is already frozen to the container walls. U.S. Pat.No. 4,388,203 discloses compositions and methods for melting alreadyfrozen material by applying de-icing compositions to the surface ofparticulate materials such as coal. These compositions also may be usedon frozen surfaces such as rail cars to thaw accumulated frozen water.This is inefficient as one would have to wait for each container ofmaterial to thaw at every transfer point before unloading and use.

Other inventors have treated the materials themselves prior to loadinginto the vehicles' storage containers. U.S. Pat. No. 4,426,409 disclosesfreeze protection polymer-systems for use in spraying particles such ascoal to reduce the cohesive strength of such particles. U.S. Pat. No.5,079,036 discloses a brine freeze control, agent which is applied toparticulate materials such as coal or mineral ores to inhibit freezingaggregation. This is uneconomical when one considers the millions oftons of such materials shipped every year and the additional costinvolved in treating the necessary materials.

A few inventors have attempted to solve the problem through preventativetreatment of the containers prior to the addition of the particulatematerial. In Nimerick U.S. Pat. No. 4,439,337, a viscous mixture isapplied to the metal surface before loading of the materials in order tofreeze proof those surfaces. Other attempts have been made to controland inhibit the freeze agglomeration of particulate materials duringtransportation and all such attempts have limitations ranging fromdifficulty of application to low cost-performance ratios. Many of thesesolutions contain ethylene glycol, sodium chloride and other substanceswhich require special disposal methods or adversely affect theenvironment. The aircraft anti-icing fluid in U.S. Pat. No. 4,698,172 isan ethylene glycol solution thickened with gel forming carrageenans.

SUMMARY OF THE INVENTION

This invention relates to environmentally responsible antifreezemulti-component compositions which are combined substantiallysimultaneous with their application to the target surfaces. Thisinvention further relates to methods of using and modifying suchcompounds to protect structures from the surrounding environment. Theuse of environmentally detrimental materials such as ethylene glycol andalkaline earth halides are avoided and instead, biodegradableingredients are utilized. More specifically, component part A is amixture which includes some percentage of polysaccharides which containacidic functional groups, and gelatinous materials in at least onesolvent while component part B contains polyvalent cations and at leastone solvent.

Part A and part B are kept separate until the time for application, atwhich time part A and part B are sprayed, preferably sequentially, andupon mutual contact produce a gel which adheres to the surface andreacts to form an antifreeze film. Other known methods of application,such as painting, may be used.

Other elements such as surfactants and non-reactive diluents are addedto meet a particular utilization requirement. Of particular importance,a dye in the coating mixture provides a more visible product. Also, anadditive can be incorporated into the antifreeze composition toneutralize the corrosive agents released by some materials. Uses for thetailored compositions of this invention include coating the inside ofrailroad cars, trucks, and vessels used for the transportation andstorage of particulate materials. Further, transported and storedarticles may be protected by forming in situ coverings, biodegradableand disposable tarps, and protective wraps. The coverings may be safelydisposed of without any substantial impact on the environment.

Uses for the compositions of this invention also include coating variousstructures to prevent or facilitate removal of ice accumulation onstructures, such as refrigeration surfaces and also including treatingaircraft parts, such as wings, to prevent or remove icing while theplane awaits take-off. At take-off, the composition which may contain arelease agent, will quickly sluff off the treated parts of the aircraft.A dye added to the composition enables the pilot to more quickly inspectaircraft icing conditions prior to and during take-off.

It is an object of this invention to provide a method of preventing iceaccumulation on exposed surfaces.

It is a further object of this invention to provide a method permittingready removal of ice accumulation from surfaces.

It is a further object of the invention to provide a method ofprotecting exposed structures from environmental harm.

It is a further object of the invention to provide a method ofcontaining particulate materials.

It is a further object of the invention to provide a method of forming aprotective film in situ over exposed structures and articles.

It is a further object of the invention to provide a method of formingin situ a disposable and environmentally safe protective film overexposed structures and articles.

It is a further object of the invention to provide a method of formingin situ semi-permanent or temporary protective films.

It is a further object of the invention to provide a method of forminginexpensive semi-permanent or temporary protective films for structuresand articles.

DETAILED DESCRIPTION OF THE INVENTION

The invention relates to environmentally preferred multi-part antifreezecompositions applied in an innovative, rapid and economical manner, toparticulate material transporting devices such as railroad cars, trucks,barges, wheel barrows and conveyor belts, as well as storage containers.These biodegradable and nontoxic antifreeze compositions assist inparticulate material removal at and below freezing temperatures bypreventing the formation of high strength ice crystals between thecontained material and the walls of the devices.

The accumulation of ice on aircraft while awaiting take-off is a safetyhazard. The decision to take-off under icing conditions has been left tothe discretion of the pilot. Unfortunately, the pilot's main method ofmaking that decision has been through personal inspection which has beenoften flawed. This invention involves a method of preventing icebuild-up over longer periods of time and assists the pilot in thedecision to take-off or reapply the anti-icing treatment by providing avisual means-of determining if ice build-up is a problem. The inventionalso may be used to facilitate removal of an ice accumulation already onthe aircraft or from other structures exposed to ice accumulation.

Antifreeze Formulations

The compositions of this invention are used to coat the sides ofrailroad cars and other vehicles or containers prior to the introductionof particulate material, to prevent ice bonding the material to thevessel surfaces. Initially the several parts of the composition areapplied onto the sides of a railroad car, for example. When the twocomponent parts react and cure, they form a thin gel film, theproperties of which can be formulated to range from water soluble towater insoluble by controlling the amount of crosslinking of thecomponent elements. The gel film prevents ice from adhering to thevessel surfaces because the film behaves as an antifreeze, preventingany water in contact with the film from forming ice crystals. Inaddition, the texture of the coating prevents any ice crystals that doform from achieving a strong physical bond with the more porous metalsurface. Although ice might still form and bond with the film, the bondbetween the ice containing material and the film will not havesufficient tensile strength to prevent the material from routinelyfalling from the vessel when the vessel is unloaded under normalprocedures. The film may be coated over the exposed surface of theloaded particulate material to prevent intrusion of water into the loadand to prevent dusting and loss of particulate material from the load.

The antifreeze compositions include multiple components which areseparately applied to the surface. Individual component parts arepreferably kept separate before their application because the rapidreaction between the components results in a semi-solid compositionwhich cannot be applied in an easy manner by a single head standardspray apparatus.

The preferred antifreeze composition employs a two part multi-componentsystem. The combination of part A and part B forms a novel compositionwith substantially improved characteristics over those of eitherindividual part. Part A includes at least one polysaccharide whichcontains acid functional groups and a gelatinous material dissolved inat least one solvent. Part A is a thick and viscous, semi-fluid gel,especially at low temperatures, and by itself has antifreeze propertieswhich prevents the formation of ice crystals. The gels of this inventionhave a freezing point dictated by the amount of water-soluble organiccompounds included in part A and part B, but preferably the gel willhave a freezing point of nearly minus 40-degrees-Fahrenheit. The finalgel strength is dictated by the type and quantity of gelatin dissolvedin part A.

The greater the percentage of gelatin, the greater the gel strength andthe higher the temperature at which the mixture will completely set-up.Gelatin reduces the vapor pressure of the composition formed and causesit to remain pliable for a longer period of time. Gelatin is alsoimpervious to all but the strongest of acids. This is desirable becausethe strong acids eluted from some particulate materials could react withsome of the polyvalent cations included in the antifreeze compositionand reduce the strength of the gel film.

The polysaccharides which contain acid functional groups useful in thisinvention include, singly or a combination thereof, cellulosic materialssuch as cellulose gum (carboxymethyl cellulose) and cation saltsthereof, including sodium, potassium, and ammonium and calcium salts;polyuronic acids such as soluble alginic acid salts, pectins and cationsalts thereof, including sodium, potassium, and ammonium salts; andmodified starches such as oxidized starches and carboxylated starches,and cation salts thereof, including sodium, potassium, and ammoniumsalts. These biodegradable materials pose no known environmentalproblems.

Gelatinous materials include gelatin, collagen, and salts thereof or amixture of such materials. Materials such as these proteins are rapidlydegraded by environmental forces.

The polysaccharides which contain acid functional groups are effectiveat levels ranging between about 0.1 percent to about 20 percent byweight but preferably between about 0.1 percent to about 10 percent byweight. The gelatinous material is added in the range of about 0.5percent to about 20 percent by weight and the preferred range is betweenabout 0.5 percent and about 12 percent by weight.

Part A may be further modified by buffers and various gums and modifiedgums, such as quar gum, locust bean gum, xanthan gum, modified quar gum,and the like, to impart varying properties to the resulting film.Various plasticizers, humectants and toughening agents may also beincluded, such as vinyl or other modified polymers.

Part A is generally dispersed in at least one solvent, preferably wateror organic glycols with low toxicity such as propylene glycol, glycerin,or a plurality of such compounds. The solvent of part A ranges betweenabout 60 percent and about 99 percent by weight, where the water amountranges between about 20 percent and 99 percent by weight and the organicelement is preferably between about 0.1 percent and about 50 percent byweight. Organic glycols, such as propylene glycol and glycerin, whenused, also have a plasticizing or elasticizing effect on the film. Otherknown plasticizers, humectants and elasticizers may also be used.

Part B contains gel stabilizing water soluble polyvalent cation salts ina solvent. The gel stabilizing polyvalent cation salts include, forexample, salts of aluminum, calcium, iron, tin, chromium, and zinc,including aluminum nitrate nonahydrate Al(NO₃)₃.9H₂ O, calcium acetate(Ca(OAc)₂), calcium citrate, and ferric chloride hexahydrate (FeCl₃.6H₂O).

The solvent in part B is in part water or an organic glycol with lowtoxicity such as propylene glycol, glycerin, alkoxytriglycols,alkoxydiglycols or hydroxyethyl pyrrolidone, and also contributeantifreeze properties to the finished film.

The polyvalent cation concentration should range between about 0.001percent and about 20 percent by weight and preferably between about0.006 percent and approximately 15 percent by weight. The water portionof the solvent ranges between approximately 20 percent and about 99percent by weight, whereas the organic element ranges between about 1percent and approximately 50 percent by weight.

The antifreeze compositions include single elements or a plurality ofelements, such as a plurality of polysaccharides which contain acidfunctional groups or a plurality of polyvalent cation salts. Differentpolysaccharides which contain acid functional groups form gels withdifferent properties when they contact polyvalent cations. A filmcontaining cellulosic material is a very smooth, even textured gelwhereas alginic acid containing gels provide a more rigid uneven gel,though much sturdier than a cellulose containing gel. Therefore,applications may require a mixture of such acid containingpolysaccharides to produce the required consistency. Similarly,different polyvalent metal cations salts have different gel stabilizingproperties and different costs, so often a combination of such saltsbest form the properties needed for a articular antifreeze compositiongel application.

The two parts are applied in the following general method. In thepreferred practice, part A and part B are preferably placed inindividual high pressure spray units and sprayed under pressure to forma gel film surface layer adjacent to and adhering to the surface of allcraft components. Preferably the separate components are applied withsprayers but mechanical methods of application including brushes,rollers, or spreaders, alone or in conjunction with spraying, can beutilized to apply some portion of the composition. Part A and part B areplaced in separate carboys connected to separate Powermate PressureWash, Model PW70-1200, pressure spray units from Coleman Powermate,Inc., Kearney, Nebr. The original spray wands are replaced with a pieceof steel pipe to which a nozzle body and a flat spray tip (Model#730308, Spray System Co., Wheaton, Ill.) are secured via a nozzle cap.The carboys are placed higher than the sprayers to prime and gravityfeed the two units. The two spray wands are secured by clamps to alength of 1"×4" board to hold them securely about 4 inches apart. Thetwo spray tips are aligned parallel to each other so the nozzle orificesare aligned vertical to the ground. The supported spray wands are heldapproximately four feet from the surface to be sprayed and produce aspray covering about a four foot wide area. The pumps of the spray unitsare activated and the solutions are released in a flat, fan-shaped finespray mist. The spray heads are moved in a horizontal motion to applythe compounds in such a manner that part A is preferably appliedslightly before part B in these antifreeze compositions so that part A'sgelatin formulation initially retains the acid containingpolysaccharides on the vessel walls for reaction with the cross linkingpolyvalent cations in part B to form a uniform gel on the surface. Thespray unit pressures used depend on the viscosity of part A and part B,and range from approximately 40 psi to approximately 1200 psi, 250 psito 350 psi is best, but about 300 psi is preferred. The effective flowrate range of part A is between about 0.2 gallon per minute and about1.75 gallon per minute but the preferred rate is about 0.5 gallon perminute. The flow rate range for spraying part B is between about 0.1gallon per minute and about 1.8 gallon per minute with the preferredrate being about 0.2 gallon per minute. The wands are moved to apply auniform layer of antifreeze ranging between about 1/1000 inch and about1/4 inch with the preferred range being about 1/32 inch and about 1/8inch thick.

Alternatively, the components are mixed in a single spray mixing nozzlesubstantially immediately prior to the outlet orifice so the mixing isimproved. The pressurized spray method of application, in addition tothe beneficial ease, speed and low cost properties, also produces abeneficial air rich environment which assists oxidation of any reducedmetal to higher valency forms for improved reactions with thepolysaccharides.

Gelatin, in combination with cellulose gum, pectin, alginic acid andother polysaccharides, prevents the strong adhesion of frozen materialto the walls of a vessel, allowing easy material removal even infreezing conditions. The invention in the form of a thin water insolublegel will be resistant to absorption by the material being transported.The water insolubility of the gel also ensures that rain, sleet and snowwhich might enter the container will not rinse the coating off the wallsof the container or render it ineffective for its intended protectiveantifreeze purpose. The gelatin containing solution should be constantlyagitated prior to being applied to ensure the solution does not gel inthe bottom of the container. Although some gel may form during long termstorage prior to application, the gel is dispersed upon subsequentheating and stirring.

The polyvalent metal salts in part B are also critical to the formationof the gels. The polyvalent metal cation salts react with the highmolecular weight polysaccharides and proteins in part A and becomeintertwined, resulting in a strong gel layer. Higher concentrations ofsuch inorganic salts rapidly form firmer, more water insoluble gels.Iron (III) appears to be the best all around polyvalent ion for thisapplication. Al (III) tends to be cost prohibitive, and Ca (II),although cost effective, does not yield as strong a gel as the others.Specifically, calcium ion cause a gel to form initially, but an excessweakens the gel formed and causes it to liquify, so the use of excesscalcium should be avoided for best results. Other metal ions are eithercost prohibitive or have adverse environmental and health effectsassociated with their use.

Each of the components, part A and part B may contain specific additiveswhich will be included based on the ultimate utilization of theinvention's compositions. For example, surfactants, such as anionicsurfactant sodium lauryl sulfate, may be utilized to decrease thesurface tension of the solution to promote bubble formation in theresulting gel film.

The following examples further illustrate the invention but are not tobe construed as a limitation on the scope of the invention. Example 1details the specific component elements and procedure for producing acomposition useful in protecting the surfaces of particulate materialstorage and transportation vessels, such as rail cars. All percentagesare calculated on a weight percent basis.

EXAMPLE 1

    ______________________________________                                        Part A              Part B                                                    ______________________________________                                         .5% cellulose gum   5% ferric chloride                                        .5% alginic acid (soluble salt)                                                                  50% propylene glycol                                       2% gelatin         45% water                                                 47% water                                                                     50% propylene glycol                                                          ______________________________________                                    

The weight of water equal to about 1/5 the calculated final weight washeated to boiling and the predetermined mass of gelatin (275 bloom,Dynagel, Inc., Calumet City, Ill.) was dissolved in this solution. Thesolution was stirred for three minutes after complete dissolution wasapparent. The solution, while still warm, was diluted with the remainingwater. The solution was vigorously agitated using a device which createda vortex into which the cellulose gum (7H, AquaIon Co., Wilmington,Del.) was gradually introduced. There was a dramatic increase in theviscosity noted during this procedure. A predetermined amount of alginicacid (heavy viscosity grade, Meer Corp., North Bergen, N.J.) wasintroduced into the solution, noting the conditions encountereddissolving the cellulose gum. The solution appeared clear, but notnecessarily colorless due to the nature of the compounds beingdissolved. The remaining quantity of propylene glycol (Eastman Chemical,Kingsport, Tenn.) was added to the vigorously stirred solution until thesolution was homogeneous.

Part B was prepared by measuring out the appropriate amount of ferricchloride hexahydrate and dissolving it in water. The quantity of thepolyvalent metal salt should be no less than about 1/16 the weight ofthe combined polysaccharides used in part A. The water solubleantifreeze, propylene glycol, was then added and the solution wasstirred vigorously for approximately twenty minutes to ensure completeand homogeneous distribution of the polyvalent metal ion.

Part A was placed in a container which gravity fed into a high pressurespraying machine (Coleman Powermate, Inc. model PW70-1200> capable ofproviding at least about 100 psi at the nozzle, and the pump was primed.Part B was then placed in a second container which gravity fed into asecond similar high pressure spray unit also capable of providing noless than about 100 psi at the nozzle, and that pump was also primed.

The spray wands of the two spray units were aligned parallel to eachother so the nozzles were vertical to the ground. The supported spraywands were held approximately four feet from the surface to be sprayedto produce about a four foot wide spray. The pumps of the spray unitswere activated substantially simultaneously and the solutions werereleased in a flat, fan-shaped fine spray mist. The pressures useddepended on the viscosities of part A and part B, but about 300 psi waspreferred. The spray heads were moved in a horizontal motion to applythe compounds in such a manner that part A was applied to the surfacefirst and part B was substantially immediately applied to part A,allowing the two components to mix and react to form a uniform gel. Thepreferred flow rate of part A was about 0.5 gallon per minute. Thepreferred flow rate for spraying part B was about 0.2 gallon per minute.The wands were evenly moved to apply a uniform layer of antifreezebetween about 1/32 inch and about 1/8 inch thick.

Part A and part B reacted to form a gel which adhered to the surface towhich it was applied. Upon setting for a short period of time the geldeveloped greater strength, became less fluid and more rigid. A gel withsufficient strength developed after about twenty minutes.

Antifreeze and Corrosion Control--Two Component System

A problem arises during the freeze-thaw weather patterns experiencedduring the transportation and storage of particulate materials, such ascoal and mineral ores. Moisture leaches compounds out of the materials,causing an adverse corrosion related degradation of the vessels. Storagecontainers and vehicles such as railcars and truck beds are made of ironcontaining metals which tend to rust and corrode excessively on contactwith these corrosive compounds. This corrosive action thereby shortensthe expected lifetime of such containers and vehicles. The problem iswell known and many unsuccessful attempts have been made to alleviateit. A corrosion control agent is incorporated into the antifreezeformulation of this invention not only to aid in the unloading of thevessels but also reduce the corrosion caused by corrosive substanceseluted from the particulate materials.

A two component system which forms a water insoluble, nontoxic,biodegradable film or gel containing a corrosion control agenthomogeneously distributed throughout, prevents the corrosion whichreduces the life of railroad cars and other devices used to transport,and store potentially corrosive particulate materials.

Possible corrosion control agents include calcium carbonate, dolomite,magnesium carbonate and other insoluble metal compounds which are ableto neutralize corrosive acids, yet are environmentally compatible withthe intended use of the contained material. The presence of calciumcompounds as corrosion control agents does not weaken the resultingantifreeze gels as soluble calcium salts do when used in similar amountsas a polyvalent cation source, because these agents are water insolubleand do not interact with the gel-forming mixture.

The spray unit pressures will depend on the viscosity of part A and partB, and range from approximately 40 psi to approximately 1200 psi, 250psi to 350 psi is best, but about 300 psi is preferred. The effectiveflow rate range of part A is held to be about twice that of part Bbecause of the desired concentration of the two parts and ranged betweenabout 0.25 gallon per minute and about 1.75 gallon per minute, but thepreferred rate is about 0.5 gallon per minute. The flow rate range forspraying part B is between about 0.1 gallon per minute and about 1.8gallons per minute with the preferred rate being about 0.2 gallon perminute. The spray wands are moved to apply a uniform layer of antifreezeranging between about 1/1000 inch and about 1/4 inch with the preferredrange being between about 1/32 inch and about 1/8 inch thick.

The resulting gel film is impervious to all but the strongest of acids.This is desirable because the strong corrosive acids eluted from thetransported material can react with the polyvalent cation to weaken thegel film. Even if some gel film deterioration occurs, theexposed-portion of the gel layer provides for additional corrosioncontrol agent to neutralize the excess corrosive-material,thereby-arresting further deterioration.

Corrosion control agents such as dolomite can be added to either or bothpart A and part B although it is not soluble in either. The corrosioncontrol agents are included in the range between about 10 percent andabout 50 percent and preferably between about 15 percent and 30 percent.Other corrosion inhibitors such as antioxidants, for example BHT, BHAand ascorbic acid, and equivalent inhibitors may be added where theparticular application protects structures or articles susceptible tooxidation. Ultra violet light inhibitors and blockers, including carbonblack and equivalent inhibitors may be added, especially where longerterm outdoor exposure is contemplated.

Gelatinous materials are also added to either or both parts so that whenthe gel is formed by the initial reaction the gelatin could begin to setand form a more rigid film. Agitation is required during mixing andapplication to maintain the gelatin and corrosion control agent insolution. If the gelatin does gel during periods of inactivity, the gelcan be reversibly brought back into solution by heating the gel over itsmelting temperature while agitating the solution.

The water insoluble nature of this gel, resulting from the gelatinousmaterial composition and the curing from the polyvalent metal cations,serves two functions. The layer will not be easily washed off byprecipitation, nor will corrosive acids rapidly penetrate it to attackthe metal walls of the treated vessel.

A mixture of individual polysaccharides which contain acid functionalgroups can be used in part A to modify the gel properties. Apreservative may be used in part A, e.g 1% propylene glycol, to preventattack by bacteria and mold if polysaccharides other than cellulosicmaterials are used. Other known preservatives may be used, such asproprionic acid, and salts thereof, copper sulfate, and otherfungistats, fungicides and bactericides.

A specific formulation and procedure for application is included inExample 2 below. The percentages are based on a total weight basis.

EXAMPLE 2

    ______________________________________                                        Part A              Part B                                                    ______________________________________                                         .5% cellulose gum   5% ferric chloride                                        .5% alginic acid (soluble salt)                                                                  47% water                                                  1% gelatin         48% propylene glycol                                      34% water                                                                     34% propylene glycol                                                          30% dolomite powder                                                           less than 1% dye                                                              ______________________________________                                    

Part A was prepared by first determining the weight of the totalsolution to be prepared. Water equal to about 1/3 the total weight washeated to boiling and the predetermined mass of gelatin was dissolved inthis solution. The solution was stirred for three minutes after completedissolution is apparent. The solution was vigorously agitated by using adevice which created a vortex into which cellulose gum was graduallyintroduced. There was a dramatic increase in the viscosity noted duringthis procedure. A predetermined amount of alginic acid was introducedinto the solution, noting the conditions maintained for the cellulosegum. The dye was introduced and the solution stirred vigorously for aperiod of no less than about one hour to ensure the complete dissolutionof the solutes. At the end of this time the solution appeared clear, butnot necessarily colorless. The dolomite powder was introduced to thissolution slowly to ensure it did not lump and remained present insolution in the same consistency as when first introduced. The propyleneglycol was slowly added and the solution was stirred for about anadditional 20 minutes to ensure homogeneity. The resulting solution wasstored after vigorous agitation.

Part B was prepared by dissolving the appropriate amount of ferricchloride hexahydrate in water. The propylene glycol was added and thesolution was stirred for approximately 20 minutes. This solution wasstored until ready for use.

The composition components were applied through an apparatus similar tothat used in Example 1. Part A was placed in a five gallon carboy andraised about two feet above the spraying mechanism to gravity feed thehigh pressure spray unit. The pump was primed and turned off. A magneticstirrer (Corning model PC-310) in the carboy as a means of agitation wasprovided to ensure the dolomite and gelatin were homogeneous throughoutthe system and did not accumulate or gel in the bottom of the container.

Part B was similarly hooked to gravity feed a second high pressure sprayunit, but no agitation means were needed since no dolomite was presentin part B.

The spray wand of each unit was snapped into a holder keeping themapproximately 4 inches apart. The units were energized substantiallysimultaneously and the combined wand unit was moved in a horizontalmotion over the surface, starting at the top of the surface. Thedistance from the surface to be covered was dictated by the pressure anddesign of the spray. The usual distance was between 3 feet to about 4feet from the surface. This allowed the solution to mix and react on thesurface.

Part A was applied at about 0.5 gallon per minute under approximately300 psi pressure and part B was applied about at 0.25 gallon per minuteunder a similar pressure.

The dolomite was suspended in the viscous part A until it reacted withpart B at the surface to form the gel film. Any dolomite in part A wasevenly distributed at the surface and ready to react with any corrosiveacids eluting from the material being carried.

A simulation of the effect of a corrosive leachate on the above preparedantifreeze gel containing a corrosion control agent was performed. Asolution of 1 molar sulfuric acid was applied to portions of theprepared antifreeze composition gel. The sulfuric acid did not appear toaffect the texture or consistency of the gel film formed through thereaction of part A and part B. The acid did not appear to dissolve anyof the gel, but a small amount of effervescence was evident as thesurface corrosion control agent neutralized the acid, emitting carbondioxide in the process.

The insoluble nature of the antifreeze gel in both water and diluteacids, plus the dolomite's reaction with any eluted acid was veryeffective in reducing a previously bothersome and costly corrosionproblem.

Aircraft and Surface Antifreeze and De-icing System

This invention also includes a method of protecting aircraft from theeffects of moisture condensing on the lifting surfaces, as well asprotecting numerous surfaces from ice accumulation, such as, duringperiods of freezing rain, snow and sleet. Specifically, the antifreezecomposition prepared for protection of vessel surfaces can be alsoapplied to aircraft as antifreeze protection during foul weather. Inaddition, this system employs a visible dye to assist the pilot indetermining if the plane is suitable for take-off or will requireadditional de-icing. This visual aid, utilizing commercially availabledyes, such as commonly used food colorings, are capable of beingobserved, even when dark to assist the pilot in determining the airworthiness of his plane. Other useful commercially available dyesinclude, natural dyes and synthetic-dyes capable of imparting easilyvisible color to the antifreeze compositions.

These antifreeze films are prepared similar to that described for theparticulate material vessel antifreeze coating compositions describedabove. These films present a slippery hard antifreeze surface which hasa tendency to repel water and ice. In addition, the polysaccharideswhich contain acid function groups are not susceptible to freezing andwill inhibit ice crystals from forming. Also, the propylene glycol ismixed in and suspended throughout the gel, presenting additionalantifreeze elements in a slow time release manner. Any precipitation orcondensation that hits the gel on the surface of the aircraft willpartially dissolve the gel film, forming a propylene glycol/watermixture which also serves as an antifreeze.

The use of a dye in the gel composition provides an added safety factor,although the visibility of the layer itself may be sufficient. Both thepilot and the ground crew will be in a position to quickly inspect andjudge whether they had adequate anti-icing protection prior to take-off.If the plane has been on the ground long enough for the gel to dissolveand dissipate, it will be visually apparent through the lack of color.FAA regulations leave the issue of additional applications of de-icer upto the discretion of the pilot. This dye component will be an addedsafety feature for all concerned. It is detectable using ultravioletlight methods to aid in inspection during the night.

The composition will be applied with modified spray units (PowermatePressure Wash, Coleman.Powermate, Inc., Kearney, Nebr.) identical tothat cited above, Part A and part B solutions are placed in carboys andplaced above the spraying unit to gravity feed the sprayers. Thepolyvalent cations form a stabilized, more water resistant layer thanfound with the foam composition in Example 3.

A water insoluble surfactant, such as dipropylene glycol monobutyl ether(butyl Dipropasol solvent from Union Carbide), additionally preventsmoisture from penetrating to the wing surface. Other known commerciallyavailable surfactants will work in this invention. The surfactants alsoact as release agents, encouraging the gel to slide off the wings duringtake-off. If one is unsure about its ability to shear during take-off,alternatively it can be physically removed such as by using highpressure air prior to take-off.

Alternatively, the invention includes an antifreeze and de-icer foamcomposition intended for use as an aircraft de-icer that produces athick water soluble foam, unlike the previously detailed gel formed withpolyvalent metal cation cross linking. In addition, this foamcomposition includes significant differences in the method of applyingthe parts to the aircraft surfaces.

The multi-component compositions include part A consisting ofpolysaccharides which contain acid functional groups, gelatinousmaterials and surfactants dissolved in a solvent system. Part B consistsof an antifreeze solution consisting mainly of hydroxy containingorganic compounds and a food color dye.

The polysaccharides which contain acid functional groups useful in thisinvention include, singly or a combination thereof, cellulosic materialssuch as cellulose gum (carboxymethyl cellulose) and cation saltsthereof, including sodium, potassium, and ammonium salts; polyuronicacids such as alginic acid, pectins, and cation salts thereof, includingsodium, potassium, and ammonium salts; and modified starches such asoxidized starches and carboxylated starches, and cation salts thereof,including sodium, potassium, and ammonium salts. These biodegradablematerials pose no known environmental problems.

Part A is generally dispersed in at least one solvent, preferably waterand organic glycols with low toxicity, such as propylene glycol.

Gelatinous materials include gelatin, collagen, and salts thereof, or amixture of such materials. Materials such as these proteins are rapidlydegraded by environmental forces.

The polysaccharides which contain acid functional groups are included inthe range between about 0.1 percent and about 10 percent but preferablybetween approximately 0.5 percent and about 2 percent. The gelatincomponent is added in the range of about 0.5 percent and approximately20 percent and the preferred range is approximately 0.5 percent andabout 4 percent. The surfactant ranges between about 0.5 percent andabout 20 percent and preferably between approximately 0.5 percent andapproximately 4 percent. The solvent for part A includes a plurality ofcompounds in the range of about 50 percent and about 99 percent wherethe water component varies between about 25 percent and approximately 50percent and the organic component is preferably between about 25 percentand about 50 percent.

Part B is simply a solvent that has about 1% food color dye dissolved init. The solvent in part B is water, an organic glycol with low toxicitysuch as propylene glycol, glycerin, alkoxytriglycols, alkoxydiglycols orhydroxyethyl pyrrolidone, or an aqueous mixture of such organicsolvents.

The components are applied to the aircraft in a different manner thanpreviously disclosed for the aircraft antifreeze gel. The composition isapplied with modified Powermate Pressure Wash spray units (ColemanPowermate, Inc., Kearney, Nebr.). Part A and part B solutions are placedin carboys and placed above the spraying unit to gravity feed thesprayers. Unlike the spraying method utilized above, part B is appliedprior to part A. Part B is simply attached to a high pressure unit whichwill disperse the mixture in a fine mist to uniformly cover the liftingsurfaces of the plane to be covered. Thus the propylene glycolantifreeze of part B initially coats the plane immediately prior tofoamed part A. The application of component part A also varies from thatpreviously described in that higher pressures, e.g. up to 1200 psi, andspray rates, e.g. 1.75 gallon per minute, are preferred. In addition,the spray from the part A wand is directed through a screen held infront of the spray tip to produce a fine bubble foam. Alternatively, acommercially available foaming machine would generate an even finerbubbled foam.

The foam is applied to the wings in a thickness range betweenapproximately one half inch and about six inches, but a thickness rangebetween about one inch and approximately two inches is generallypreferred. Applying part A as a foam presents several long termbenefits. The foam adheres to the wing due to its viscous nature andinsulates the wing from moisture condensing onto the wing due to thecold fuel in the aircraft. Due to the very stable nature of the foam itprovides a stable foam for a period of up to about six hours. Anyprecipitation falling contacts the foam and as the moisture works itsway through the foam it dissolves the organic antifreeze agents andlowers the freezing point of the water. By the time the moisture reachesthe wing itself, it has achieved antifreeze characteristics and will notfreeze to the metal.

The dye in the composition is visible to the eye or with the use ofultraviolet light at night. As the moisture falls, the water extractsthe dye from the solution and the visibility of the dye decreases as theamount of anti-icing protection decreases. The amount of dye or itscolor can be calibrated to determine the safe level of protection beforeice formation becomes a serious safety hazard.

The invention as it is applied to the parts of aircraft as de-icers andantifreeze is more specifically described in the embodiment in Example3. All percentages are calculated on a weight percent basis.

EXAMPLE 3

    ______________________________________                                        Part A             Part B                                                     ______________________________________                                         .5% cellulose gum 99% propylene glycol                                         2% gelatin        1% dye                                                      2% lauryl sulfate                                                             48% propylene glycol                                                        47.5% water                                                                   ______________________________________                                    

Part A was prepared by heating approximately one liter of water toboiling. About forty grams of gelatin (275 bloom) were added to theboiling water. Before the solution cooled, approximately one liter ofpropylene glycol was added to the above solution to make a combinedvolume of approximately two liters. About ten grams of cellulose gumwere added to the vigorously stirred solution, noting that the viscosityof the solution increased as the cellulose gum dissolved. This solutionwas stirred for a period of at least about one hour or until thesolution was clear, homogeneous and lump free. Approximately forty gramsof previously dissolved lauryl sulfate in water were added to thissolution.

The composition was applied with modified Powermate Pressure Wash sprayunits (Coleman Powermate, Inc., Kearney, Nebr.). Part A and part Bsolutions were placed in five gallon carboys and placed about two feetabove the spraying unit to prime and gravity feed the sprayers. Unlikethe spraying method utilized above, part B was applied to the surfacessubstantially immediately before part A by simply moving the two securedspray wands in a motion so part B went on before part A. Part B wasattached to a high pressure unit which dispersed the mixture in a finemist to uniformly cover the lifting surfaces of the plane to be covered.The propylene glycol antifreeze initially coated the plane immediatelyprior to foamed part A. The application of component part A occurred ata back pressure of about 1200 psi and a spray rate of about 1 gallon perminute. In addition, the spray from the part A wand was directed througha 90 mesh screen held about two inches in front of the spray tip toproduce a fine bubble foam.

The foam was applied to the wings in a thickness range betweenapproximately one inch and approximately two inches.

The material described in Example 3 is also a highly effective releaseagent to prevent ice build-up, or to facilitate removal of ice, fromrefrigeration pipes and other surfaces and structures where iceaccumulation is undesirable. The material may be applied with or withoutfoaming and any ice accumulation can be readily removed by air spray ormechanical contact.

EXAMPLE 4

A protective film for exposed structural steel may be prepared as a twopart system as follows:

Part A, the vehicle, is prepared, as described in Example 1, as asolution/dispersion containing

3 parts by weight sodium alginate, heavy viscosity (Meer Corporationfood grade)

82 parts by weight water

15 parts by weight propylene glycol

Part B, the reactant, is prepared, as described in Example 1, as asolution containing

5 parts by weight calcium chloride

95 parts by weight water

Parts A and B are sprayed through a dual head spray applicator asdescribed in Example 1 onto structural steel members, such as flatsteel, reinforcing bars and I-beams. The film of coating forms in situon the steel members and forms a substantially continuous film coveringthe members. The film will dry and be continuous in about 30 minutes.The steel members and covering film may be left exposed in an outdoorstorage yard. The film may be stripped from the steel members anddisposed of by flushing with a pressurized water stream. The steelmembers will be substantially less corroded than an unprotectedcomparison piece stored under equivalent conditions.

EXAMPLE 5

A protective film for an exposed composite concrete pier form may beprepared as a two part system as follows:

Part A, the vehicle, may be prepared, as described in Example 1, as asolution/dispersion containing

3 parts by weight high viscosity sodium alginate (Meer Corporation foodgrade)

90 parts by weight water

7 parts by weight glycerin

Part B, the reactant, may be prepared, as described in Example 1, as asolution containing

5 parts by weight calcium chloride

95 parts by weight water

Parts A and B are sprayed through a dual head spray applicator, asdescribed in Example 1, onto a tubular composite concrete form oflaminated reinforced paperboard. The film of coating forms in situ onthe laminated tube and forms a substantially continuous film coveringthe laminated tube. The film will dry and be continuous in about 30minutes. The laminated tube and covering film may be left exposed in anoutdoor storage yard, for example, for 30 days. At the end of that timethe film may be stripped from the laminated tube and disposed of byflushing with pressurized water or by scraping. The laminated tube willbe in substantially better condition than an unprotected comparisonpiece stored under the same conditions. The protected piece will notexhibit any substantial delamination or degradation from absorbedmoisture. The unprotected piece will suffer environmental degradation.

EXAMPLE 6

A protective film for exposed particulate material may be prepared as atwo part system as follows:

Part A, the vehicle, may be prepared, as described in Example 1, as asolution/dispersion containing

3 parts by weight sodium alginate (high viscosity) Meer Corporation foodgrade

90 parts by weight water

7 parts by weight glycerin

Part B, the reactant, may be prepared, as described in Example 1, as asolution containing

5 parts by weight calcium chloride

95 parts by weight water

Parts A and B are sprayed through a dual head spray applicator, asdescribed in Example 1, onto the surface of a gravel load contained in atruck bed. The film of coating forms in situ on the upper exposedsurface of the gravel load and forms a substantially continuous filmcovering the gravel load and confining the gravel to the vehicle. Thefilm covered load may be subjected to bumps and agitation by drivingover surface bumps at speeds consistent with work conditions. The filmwill retain loose particles in the vehicle. The load may be dumped intostorage. The film will not interfere with removal of the load from thevehicle and the load will break up into loose gravel when dumped.

EXAMPLE 7

A protective film for landfill and pit lining may be prepared as a twopart system as follows:

Part A, the vehicle, may be prepared, as described in Example 1, as asolution/dispersion containing

3 parts by weight sodium alginate (heavy viscosity) Meer Corporationfood grade

90 parts by weight water

7 parts by weight propylene glycol

Part B, the reactant, may be prepared, as described in Example 1, as asolution containing

5 parts by weight calcium chloride

95 parts by weight water

Parts A and B are sprayed through a dual head spray applicator asdescribed in Example 1 onto a landfill pit to line the bottom and wallsof the pit with a thick flexible film. The film of coating forms in situon the bottom and walls of the pit and forms a substantially continuousfilm. The pit may be subsequently filled with compacted landfill refuseand a covering film applied by spraying, as described herein. The pitmay then be covered with a compacted earth overburden to seal the pit.The film acts to seal the refuse and retard leaching of the pit contentsinto the environment.

EXAMPLE 8

A protective film for lining dry chemical cars, such as thosetransporting urea or potash, may be prepared as a two part system asfollows:

Part A, the vehicle, was prepared, as described in Example 1, as asolution/dispersion containing

2.4 parts by weight sodium alginate (heavy viscosity) Meer Corporation,food grade

87.6 parts by weight water

10 parts by weight glycerin

Part B, the reactant, was a dry solid of anhydrous calcium chloride,fine powder.

Part A was sprayed through a spray applicator onto the surfaces of anopen railway car. When the surfaces of the car were covered by part A, adusting of the powdered calcium chloride was applied to lightly coverthe tacky film of part A. The film was dry and continuous in about 30minutes.

Thus there has been shown and described novel means for environmentallysound antifreeze and covering compositions and uses without ethyleneglycol or alkaline earth halides. The present invention fulfills all theobjects and advantages set forth above. It will be apparent to thoseskilled in the art, however, that many changes, modifications,variations and other uses and applications for the subject invention arepossible. All such changes, modifications, variations and other uses andapplications which do not depart from the spirit and scope of theinvention are deemed to be covered by the invention, which is limitedonly the claims which follow.

We claim:
 1. A method of applying an antifreeze composition to form a protective film, the antifreeze composition being comprised of:a part A component comprised of a water containing solution of an alginic acid composition containing acid functional groups, the alginic acid composition being selected from the group consisting of sodium, potassium and ammonium salts of alginic acid, and a separate part B component comprised of a water containing solution of a polyvalent cation salt selected from the group consisting of soluble calcium, aluminum and iron salts, the alginic acid composition being present in part A in an amount between about 0.01 to 20 percent by weight, and the polyvalent cation salt being present in part B in an amount between about 0.001 and 30 percent by weight, and wherein part A and part B are sprayed through pressurized sprayers, at flow rates over about 0.1 gallon per minute, mixing said components together and allowing the composition to react and form a cross linked antifreeze gel layer.
 2. The method of claim 1 wherein part A also contains a gelatinous material.
 3. The method of claim 1 wherein part A also contains between about 0.5 and 12 percent of a gelatinous material.
 4. The method of claim 1 wherein the sprayers mix the components immediately prior to applying to said surface.
 5. The method of claim 1 comprising spraying one of said components, immediately prior to spraying the other component, through separate pressurized sprayers with separate nozzles.
 6. The method of claim 1 wherein the components are applied at flow rates between about 0.2 gallon per minute and 1.8 gallons per minute.
 7. The method of claim 1 wherein the gel layer is between 1 to 250 mil thick.
 8. The method of claim 1 wherein the gel layer is between 30 and 125 mil thick. 